:root{
  --bg: #f3f4f6;         /* gris clair */
  --card: #ffffff;
  --text: #111827;       /* texte très lisible */
  --muted: #4b5563;
  --border: #e5e7eb;
  --shadow: 0 10px 25px rgba(0,0,0,0.06);
  --focus: #2563eb;
  --btn: #111827;
  --btn2: #374151;
}

*{ box-sizing: border-box; }

body{
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Noto Sans", "Liberation Sans", sans-serif;
  background: var(--bg);
  color: var(--text);
}

.container{
  max-width: 860px;
  margin: 28px auto;
  padding: 0 16px;
}

.header{
  margin-bottom: 16px;
}
.header h1{
  margin: 0 0 6px;
  letter-spacing: 0.2px;
  font-size: 2rem;
}

.logo{
  width: 70px;
  height: auto;
  border-radius: 90px;
  display: grid;
  place-items: center;
  display: block;
}
.subtitle{
  margin: 0;
  color: var(--muted);
}

.card{
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 18px;
}

h2{
  margin: 0 0 14px;
  font-size: 1.25rem;
}

.form{
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.field label{
  display: block;
  font-weight: 650;
  margin-bottom: 6px;
}

input, select{
  width: 100%;
  padding: 12px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fafafa;
  color: var(--text);
  font-size: 1rem;
}

input:focus, select:focus{
  outline: 3px solid rgba(37, 99, 235, 0.25);
  border-color: var(--focus);
}

.actions{
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 2px;
}

.btn{
  appearance: none;
  border: 0;
  border-radius: 12px;
  padding: 12px 16px;
  background: var(--btn);
  color: #fff;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.05s ease, opacity 0.2s ease;
}

.btn:hover{ opacity: 0.95; }
.btn:active{ transform: translateY(1px); }

.btn-secondary{
  background: var(--btn2);
}

.result{
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px dashed var(--border);
}

.result-title{
  margin: 0 0 6px;
  color: var(--muted);
  font-weight: 650;
}

.result-value{
  font-size: 2rem;
  font-weight: 850;
  letter-spacing: 0.2px;
}

.result-note{
  margin: 8px 0 0;
  color: var(--muted);
}

.footer{
  margin-top: 14px;
  color: var(--muted);
  font-size: 0.95rem;
}

.mono{
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}